(A) Field of Invention
This invention is directed toward a panel for use in closures, and more particularly toward an insulated closure panel for use in rolling closures. The invention is also directed toward closures incorporating the closure panels.
(B) Description of the Prior Art
It is known to provide insulated panels for use in rolling closures. Each insulated panel comprises inner and outer metallic walls connected together at the sides of the panel. A male hinge element is located on one side of the panel and a female hinge element is located on the other side of the panel. One panel is pivotally connected to the next by slidably connecting the male hinge element of one panel in the female hinge element of the adjacent panel. Each panel is filled with an insulating material.
These known insulated panels have disadvantages however. The metal-to-metal contact between the outer and inner walls at the sides causes heat loss by conduction from the inner wall to the outer wall. Also, the use of metallic inner and outer walls makes the panels quite heavy and expensive. Further, the hinge elements on each panel are formed by bending the walls of the panels which bending step adds to manufacturing costs making the panels expensive. In addition, inadequate sealing between adjacent panels results in higher heat loss through the closure incorporating the panels.
It is known to provide an improved insulated closure panel which comprises an outer metallic panel section and an inner thermoplastic panel section. The inner panel section is tubular and is adhesively mounted to the back surface of the metallic panel section. The inner panel section is filled with insulation. The inner thermoplastic panel section lightens the closure panel and prevents heat loss by conductance between the inner and outer surfaces of the panel. However, the inner panel section does not extend completely across the outer panel section thereby reducing the panel's insulating properties. In addition, the adhesive connection between the inner and outer panel sections requires an additional manufacturing step and additional materials. The adhesive connection could also fail if the adhesive is not properly applied. This improved closure panel also has poor sealing between adjacent panels resulting in higher heat loss through the closure incorporating the panels.